Foam prevention



Patente July 11, 1194? F PREVENTION Sidney D. Wells, Combined Locks,Wis., assignor to The Institute of Paper Chemistry, a corporation ofWisconsin No Drawing. Application March 16, 1944, Serial No. 526,823

1 Claim. l

The invention relates to foam prevention and is of particular value inpreventing foam from developing on the surface of stock which is fed topaper-making equipment.

When making various types of paper, for example, printing papers, thestock of which contains a substantial percentage of groundwood,considerable difficulty is encountered by reason of the development offoam on the surface of the stock feed in various parts of the equipmentdue to conditions of operation which frequently are necessarily inherentin the paper-making process or operation and cannot be convenientlychanged in view of practical operating requirements.

The object of the present invention is to provide a treatment or methodof operation which may be applied to existing paper-making operationswithout the necessity of making any material change in the standardmake-up or furnish, or in the operating technique.

In general, it may be said that the invention contemplates that thereshall be added or fed to the stock or paper-making furnish a relativelysmall quantity of a water-oil emulsion of special type. Preferably thisemulsion is fed to the stock continuously at a point somewhere betweenthe beater and the slice. When a condition develops which will, anddoes, result in the formation of foam, the feed of anti-foaming agent iscommenced until the foam is destroyed, and thereafter, usually the feedof anti-foaming agent may be reduced considerably in view of the factthat it is not necessary to feed as much anti-foaming material toprevent formation of foam as is required to destroy foam which hasalready developed on the stock.

The anti-foaming agent which has been found to be of value in thisconnection is an aqueous emulsion comprising a siccative oil, preferablya vegetable oil such as linseed oil, China-wood oil, or other vegetableoil, which oil preferably has been partially oxidized or subjected to aboiling treatment, which siccative oil is diluted with a mobile inertsolvent such as kerosene or similar mineral oil which is not toovolatile. The emulsion is stabilized by the use of any suitablestabilizing agent known to be of value in stabilizin a water-oilemulsion of the composition above referred to. For example, onestabilizing agent 'Which has been successfully used is a materialmarketed under the brand name Stanolind No. 250, which material isderived from the acid oil resulting from oil refining. It contains thesulfuric acid compounds of components found in natural petroleum and iscalled mahogany soap.

In preparing a supply of the de-foaming agent above referred to, thestabilizin agent is preferably first dissolved in the inert solvent, andthen the resulting solution is thoroughly mixed with the siccative oil.Then this combined mixture is diluted with about twice the weight ofwater and thoroughly mixed and emulsified by vigorous agitation with ahigh speed propeller type mixer, for example a mixer of the type knownon the market as a Lightning mixer.

After the emulsion has been formed in the above manner, it may be keptfor several days without danger of settling and is of such consistencythat it can be fed drop by drop to the stock feed.

Specific example Boiled linseed oil gals 15 Kerosene ls-.. 28 StanolindNo. 250 lbs 48 Water als These materials are all combined according tothe practice previously outlined.

In the case of a paper machine making four tons of groundwood baseprinting paper per hour, the most troublesome foam which develops due toany normal condition can usually be broken by feeding 3 drops of thisemulsion per second to the riilies between the fan pump and the screens.After the foam has been broken and has disappeared, the feed of emulsionmay be considerably reduced, for example, to 1 drop per second, so thata twenty-four hour run will require only a very few gallons of theemulsion in order to obtain satisfactory results.

The scope of the invention should be determined by reference to theappended claim.

I claim:

An aqueous emulsion the components of which are kerosene, boiled linseedoil, mahogany soap,

3 and Water in the proportions of 28 gallons of kerosene, 15 gallons ofboiled linseed oil, 48 pounds of mahogany soap, and 100 gallons ofWater, prepared for use as an agent for preventing foam on the stockfeed of a paper-making, machine.

SIDNEY D. WELLS.

REFERENCES CITED Number UNITED STATES PATENTS Name Date Bradshaw Nov.24, 1931 Heckel May 2, 1933 Mathias June 26, 1934 Weik Dec. 10, 1935Fritz Dec. 8, 1942 Fritz et a1 Apr. 25, 1944 Evans et a1 Apr. 17, 1945FOREIGN PATENTS Country Date Number Great Britain May 23, 1935

